The spatial modelling of high-latitude plant richness and refugia in a changing environment

• Main Author: Niskanen, Annina
• Other Authors: Hickler, Thomas, University of Helsinki, Faculty of Science, Department of Geosciences and Geography, Helsingin yliopisto, matemaattis-luonnontieteellinen tiedekunta, geotieteiden ja maantieteen laitos, Helsingfors universitet, matematisk-naturvetenskapliga fakulteten, institutionen för geovetenskaper och geografi, Luoto, Miska, Heikkinen, Risto
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Helsingin yliopisto 2018
• Subjects: Arctic; Climate change; Fennoscandia
• Online Access: http://hdl.handle.net/10138/232601

Arctic-alpine regions are facing notable climatic changes. Improved understanding is needed of how these changes cascade into species distributions and what they might mean for the Arctic-alpine realm. These high-latitudes are expected to be susceptible to change. This vulnerability highlights the importance of identifying drivers of Arctic-alpine species and the landscape features that support their persistence. This thesis examines the determinants of present-day refugia; investigates drivers of plant richness and how projected hotspots coincide with conservation areas; forecasts refugia for species persistence and their connection to topo-geological features; and predicts forthcoming changes in species distributions and sensitivity, and whether these are affected by biogeographic history. Multiple statistical modelling approaches were combined with extensive data on species occurrences and environmental drivers. Models were built for refugia, vascular plant species, and various aspects of species richness. Changes in responses were projected across climate scenarios within Fennoscandia. The pronounced climate-dependency of high-latitude species and refugia suggests climate change to have substantial impact on the region’s flora. However, incorporation of topo-geological drivers improved models and forecasts of refugia. Refugia may be especially important for species persistence under severe climate change, particularly for rare or threatened species. Diversity hotspots exhibited low congruence due to variance in key drivers: total species richness prospers in warmer conditions; hotspots of range-restricted species occur near the cooler Northern Scandes. Protected areas in northern Fennoscandia offer limited coverage for these culminations of biodiversity. The climate change sensitivity of high-latitude flora depends not only on predicted warming, but on regional geography and species biogeographic history. Contrary to global estimates these findings do not predict poleward range center shifts. Northern Arctic ...